Flight MH370 Debris Hunt: Day Nine At A Glance

Search teams from six countries are scouring the southern Indian Ocean for the wreckage of flight MH370.

Officials sharply narrowed the search zone based on the last satellite signals received from the Malaysia Airlines plane.

Despite being scaled down, it is still estimated to be around 1.6 million sq km (622,000 sq miles) - nearly seven times the size of Britain.

Video:The Sonar Search For The Black Box

The Australian Maritime Safety Authority, which is coordinating the hunt, said much of Wednesday's focus would be on a 80,000 sq km (30,900 sq miles) swathe of the ocean.

A total of 12 planes and two ships from the US, China, Japan, South Korea, Australia and New Zealand are taking part.

A Chinese Ilyushin IL-76 was the first aircraft to depart for the area, leaving around 8am local time.

China has also sent the polar supply ship Xue Long, with other Chinese vessels on their way.

The US Navy is also sending a P-8 Poseidon to the remote area, which is about 1,550 miles (2,500km) southwest of Perth.

Video:Flight MH370: A Special Report

The Australian naval vessel HMAS Success will conduct a surface sweep of the region where two objects, possibly debris, were spotted this week.

Australia also sent out an AP-3 Orion this morning. It will send another out later in the day.

New Zealand's P-3 Orion left for the zone about an hour after the Chinese plane left the base.

And South Korea has joined the search for the first time, also offering up a P-3 Orion, which will head to the area later today, along with a Japanese P-3 Orion.

As well as the military planes, five civilian aircraft are scouring the ocean for any sign of the plane.

Video:MH370: Inside The Situation Room

The efforts will be aided by the deployment of an American advanced sonar device to help locate the plane's "black box" flight data recorder.

Malaysia Airlines confirmed the battery which powers the black box will emit a locator signal of 30 days, once activated by contact with water, giving searchers less than two weeks to find the crash site.

Those efforts will be crucial in finding out why MH370 veered so far off its intended course from Kuala Lumpur to Beijing.